Normalizing and tempering oven



June 2, 1942.- H. CASE NORMALIZING AND TEMPERING OvEN Filed May 24, 1940 5 Sheets-Sheet 1 A T TO/PNE Y @QN ma u m m QM k M Q June 2, 1942.' H. cAsE 2,285,250

NORMALIZING AND TEMPERING OVEN Filed May 24, 1940 3 Sheets-Sheet 2 INVENTOR. /(4/\0LD C455 BY 544mg A Ta A EY imw June 2, 1942. H. CASE NORMALIZING AND .TEMPERING OVEN Filed May 24, 1940 5 Sheets-Sheet 3 IIWIII" 3 hullm marl/I994 INVENTOR. /7//)/P01. 0 C435 4 T TOR/V5) Patented JuneZ, 1 942 {L UNITED V STATES PATENT -OFFICE j Y 2,285,250. 1 I I onMALIzING AND, TEMPEBING OVEN Harold Case, New;Yo'rk, N. Y. 1

Application May'24, 1940, Serial No. 336,939 "9 Claims. (01.263 9) The invention relates to normalizing and tempering ovens and more particularly to ovens for heat treating sugar cane knives which generally consist of an iron shank to which aspecial steel cutting tip is welded. In use these knives are attached, in predetermined numbers, to hubs by a means of which said knives are revolved at high section on the line 8-8 of Fig. 7; Fig. 9 is aview showing a cane knife supporting'bar; Fig. 10 illustrates a tool for inserting the cane knife into the oven for either normalizing or tempering;

speeds, for the purpose of cutting the sugar cane into small pieces prior to passage into the mills.

v Due to the existing methods of fabricating the knife shankand the steel knife .tip, these materials are not homogeneous. Inpractice, strains are also developed along the welded joints where theiron'shanks and the steel cutting tips are united, which strains are due to difierent expansion characteristics and also to the contraction of the welding material when cooling down. If, in operation, these knives are sub- ,jected to the effects of high centrifugal force and strike the cane mat at high velocity, said knives are liable to break and cause damage to the cane crushing rolls andother'parts of the associated apparatus.

Bynormalizing or evenly heating and by-ekposing the whole knives toaneven heat over a predetermined periodof time, and then permitting said knives to cool off slowly, all strains inthe materials are relieved and the knives are rendered tough, homogeneous and pliable throughout.

Theinvention has for its object .to provide a novel oven whereby the'normalizing of the knives may be efficiently effectedin a simple manner and without requiring any particular. skill on the part of the atendants. The. invention further contemplates theprovision ,of an oven which in addition may be used for tempering or hardentrate an example. of the invention without defining its limits, Figs. 1 and 2 are corresponding Fig. 11 is a faceview illustrating a preferred form of gate'construction; and Fig. 12 is a longi tudinal section thereof on the. line 12-12 of- Fig. 1 1.

As shown in the drawings, the novel oven comprises'a body consisting of a bottom wall l5, an upright rear wall l6; atop wall [1, an upright front wall 18, and opposite side walls l9, allof said walls being constructed ofvstandard fire bricks or their equivalent; The front wall I8 includes two upward extensions 20 spaced apart as shown in Fig.. 3 for thepurpose to be more fully set forth hereinafter.

At itslower portion the oven is, provided interiorly with a combustion space: or chamber 2| of predetermined dimensions, asfor instance 9" wide, 9 high and 27%;" long. Above the combustion chamber II is located a relatively narrower normalizing chamber orspace 22 which extends over the full length of the combustion chamber- 2| andQthroughout-its bottom come municates therewith. Two pairs of preferably cast iron, tuyres 23 and 24 are set intothe opposite side walls l9 and extendtransversely therethrough at points immediately above the combustion chamber 2| to establish communication between the atmosphere and the interior of the oven for balancing the gas pressure inside the combustion chamber 2| as will appear more fully hereinafter. The tuyres 23 comprising one of the pairs are located in axial registry with each other in the opposite side walls l9 and the tuyres 24 comprising the; other pair are in corresponding axial registry with each other in spaced relation to the tuyres 23; in addition to their other functions, the tuyres .23 and 24 *serve asgbearings for supports 25 for the cane knives, said supports 25 as shown'in Fig. 9 each consisting of a bar preferably pointed at one end longitudinal sections of the oven showing acane knife inserted for normalizing,andfor tempering the steelknife tiprespectively; Fig. 3 is a front elevation of the oven; Fig. 4 is a similar view with the oven gate omitted; Fig. 5 is a crosssection on the line 5-5 of Fig. 1; Fig. 6 is an enlarged detail view illustrating a pulley or sheave mounting which forms part of the gate mechanism; Fig. 'I ,is an end view of a tuyere odied i he o en; Fi 81. lon tudinal and provided with ahandle 26 at the other end.

The front wall l8.-is provided with anopening 2! also serves as an aperture through which the cane knives may be inserted into the oven as will appear more fully hereinafter.

The open front or longitudinal opening of the flue 2'! is closed by means of a gate 28 slidably mounted between guide angles or members 29 which may be fixed in place in any suitable manner. In the preferred arrangement illustrated in the drawings, the guide angles 29 at their upper ends are welded to a flat cross member 30 which in turn is mounted by means of spacers 3| upon upright angle irons 32 extending lengthwise of the upright edges of said front wall l8. The lower ends of the guide angles 29 are welded to a spacer angle 33 which in turn is Welded to a plate 34; the latter is welded at its opposite vertical end edges to the upright angle irons 32. The latter project upwardly beyond the top wall I! and support a cross-member or angle iron 35 which preferably is connected with said angle irons 3-2 by welding, and carries two sheaves or pulleys 36 rotatably mounted in spaced relation to each other by means of bolts 31. A chain 38 or its equivalent passes over said sheaves or means whereby the gate 28 may be adjusted to provide access to the longitudinally open flue 21 for insertion of the knives into the oven. A fire brick 21 is slidably fitted between the front wall extensions 20 and is movable on the top wall IT to act as a damper for regulating the gas velocity through the flue 21.

The gate 28 as illustrated in Figs. 11 and 12, preferably comprises a rectangular frame. composed of angle irons 28"" welded together and provided with a sheet metal member 28'" welded in place, a plurality of rods 28 being welded in transverse relation to each other within the angle iron frame for the purpose of holding plastic fire brick 28 in position, said fire brick being tamped into place so as to project over the edges of the angle iron frame 28 as shown in Fig. 1, and to leave a tapering or cone-shaped hole 28 in registry with an opening 28 cut in the sheet metal member 28 to provide a peep hole. When the gate 28 is mounted between the guide angles 29, the plastic fire brick 28 faces and slidably engages the front wall I8 of the oven and forms the front wall of the flue 21. A. refractory ignition tile 40 is setinto the front wall 18 in registry with the combustion chamber 2| and behind the plate 34; the latter is provided with an opening 4| in registry with the small end of a cone-shaped or tapering opening 42 in the ignition tile 40 which opening 42 flares outwardly toward and communicates with the combustion chamber 2| An oil burner 43 is externally mounted on the plate 34 by means of bolts 44 or the like, and has its nozzle located in concentric registry with the openingsi4l and 42; the oil burner 43 To further increase the stability of the structure, the lower ends of the upright angle irons 32 may be tied together by means of an angle iron or member 4! in welded connection with said angle irons 32. In practice, the oven as a whole may be supported upon a suitable base 48.

When the oven is to be put into operation, the oil and air mixture is ignited inside the ignition tile 40 and completely burned in the combustion chamber or space 2!, the hot gases passing from the latter upwardly and through the normalizing space 22 and up to the flue 21 to the atmosphere. The gate 28 occupies its closed position and the damper brick 27 is so adjusted over the top of the flue 21 that there is only a slight suction of air into the interior of the oven through the tuyeres 23 and 24. The hot gases of combustion pass evenly through the whole length and height of the normalizing space or chamber 22 and heat the walls thereof to a red heat, the gases passing from said normalizing space or chamber 22 to and through the narrow flue 2! to the atmosphere.

As soon as the walls of the normalizing space or chamber 22 are red hot, the gate 28 is opened by pulling down on the weight 39, and the cane knife supports 25 shown in Fig. 9 are inserted through the tuyeres 23-23 and 24-24 so as to transversely span the normalizing space or chamber 22 immediately above the combustion chamher or space 2|. By means of the special tool A shown in Fig. 10, which for normalizing purposes fits slidably over the steel cutting tip B of the cane knife, the latter is inserted into the normalizing space 22 so as to rest therein in a vertical position in the center of this space or chamber and upon the supports 25, as shown in Fig. 1. The gate 28 is then closed whereupon the cane knife is exposed to the reflex heat radiated by the fire brick composing the walls of the oven and by the hot gases passing up from the combustion chamber or space 2|. During this stage, the cane knife becomes evenly heated from the end of the shank C to the point of the tip B. By means of the sliding damper brick 2! and the air register adjustment of the oil burner 43 as well as the air and oil adjustment thereof, any temperature desired or required may be maintained within the oven, so that there is no danger of damaging the material during the normalizing process regardless as to how long said knife may be left in the oven and without regard to what varying crosssections it may have. After the knife has been exposed to the heat the predetermined required length of time, the gate 28 is raised to an open position and by means of the tool A, the cane knife is withdrawn from the oven and buried in hot ashes there to gradually cool off.

When utilizing the oven for tempering the cane knives, the cane knife support 25 previously inserted through the tuyeres 23--23 i withdrawn and the cane knife by means of the special tool A which previously has for this purpose been connected with the shank C, is inserted into the oven so as to rest only upon the cane knife support 25 which extend through the tuyres 24-24; as shown in Fig. 2, the cutting tip B of the cane knife extends at a downward inclination from the cane knife support 25 and projects partly into the combustion chamber or space 2| while the shank C of'the knife projects into the opposite direction and exteriorly of the oven as shown in Fig. 2, after which the gate is lowered to approximately the position shown therein. By decreasing the flame of the oil burner'4-3 and reducing the amount of air admitted through the air register thereof, air in a predetermined amount will be drawn into the interior of the oven through the tuyres 23-43 which causes the flame to be drawn closer toward the ignition tile 40 and therefore completely envelopes the cutting tip B of the knife. By properly adjusting the damper brick Z'l it is possible to draw this part of the knife to any desired heat. As soon as the predetermined degree of heat is reached, the caneknife is withdrawn from the oven by means of the tool A and quenched in the conventional manner.

By normalizing or evenly heating the knife .and by keeping the whole of said knife exposed to an even heat. over a predetermined period of time, and then letting said knife cool off slowly, all strains in the material are relieved and the entire knife is renderedtough, homogeneous and pliable. Similarly, the tempering of the. knife is accomplished with maximum efficiency and without material knowledge or experience on the part of the attendant.

hile the illustrated and described oven is primarily designed for the purpose of normalizing and tempering cane knives, it is obvious that it may be used with equal efficiency for other purposes.

Various changes in the specific forms shown and described may be made within the scope of the claims, Without departing from the spirit of the invention.

I claim:

1.' In an oven for heat treating materials, the combination of a body provided with a combustion chamber and a relatively narrower heat treating chamber lying above the same and in communication with said combustion chamber throughout the bottom of said heat treating chamber, and having a flue in communication with the latter, means for supporting the material to be treated within said heat treating chamber, means for developing heat within said combustion chamber, and means for regulating the velocity of the combustion gases through said 2. An oven for normalizing and temperin sugar cane knives including a front wall, said oven being provided with a combustion chamber and a normalizing chamber located above saidcombustion chamber, said normalizing chamber being of less transverse dimensions than said combustion chamber and throughout its length communicating with said combustion chamber, said front wall having an opening of less width than said normalizing chamber in communication therewith and extending transversely through said front wall and terminating at the' top of said oven in communication with the atmosphere to constitute a flue, a refractory ignition tile in said front wall having a conical opening in communication with said combustion chamber, an oil burner having its nozzle in registry with said conical opening, tu'yres located in opposed registering pairs in communication with the interior of said oven and with the atmosphere, rods arranged to removably fit into each pair of tuyeres and to bridge the interior space therebetween to constitute supports for the cane knives, a gate slidably mounted on the external face of said front wall to close the opening thereof, means for adjusting said gate to provide access to said opening for insertion of the knives into the oven for selectively normalizing or tempering said knives, and a damper slidably adjustable over the exit end of said flue for regulating the velocity of the combustion gases therethrough.

.3. An oven for normalizing and tempering sugar cane knives including a front wall, said oven being provided with a combustion chamber and a normalizing chamber located above said combustion chambensaid normalizing chamber being of less transverse dimensions than said combustion chamber and throughout its length communicating-with said combustion chamber, said front wall having an opening, of les width than said normalizing chamber in communication therewith and, extending transversely through said front wall andterminating at the top of said oven in communication with the atmosphere to constitute a flue, an oil burner having itsnozzle in communication with said combustion chamber, tuyres located in opposed registering pairs in communication with the interior of the oven and with the atmosphere, means arranged to removably fit into each pair of tuyeres and to bridge the interior space therebetween to constitute supports for the cane knives, a gate slidably mounted on the external face of said front wall to close the opening thereof, means for adjusting said gate to provide access to said opening for insertion of said knives into the oven for selectively normalizing or tempering said knives, and means for regulating the velocity of the combustion gases through said flue.

4. An oven for normalizing and tempering sugar cane knives comprising a body having a combustion chamber and a normalizing chamber lying above the same, said normalizing chamber being of less width than said combustion chamber and throughout its length communicating with saidcombustion chamber, a flue in said body connected with said normalizing chamber and longitudinally open and having its exit end in communication with the atmosphere, a gate slidable over the longitudinal opening of said flue to close the same, means for adjusting said gate to provide access to said opening for insertion of said knives into said oven, tuyeres in communication with the atmosphere and the interior of said oven for balancing the gas pressure in said combustion chamber, means cooperating with said tuyeres to control the passage of air therethrough and to provide supports interiorly of the oven for said knives, and means for regulating the velocity of the combustion gases through said flue.

' 5. An oven for normalizing and tempering sugar cane knives comprising a body having a combustion chamber and a normalizing chamber lying above the same and throughout its bottom being in open communication with said combustion chamber, a longitudinally open flue in said body connected withsaid normalizing chamber and having its exit end in communication with the atmosphere, a movable closure for closing the longitudinal opening of said flue to form a wall. thereof and adjustable to provide access to said opening for insertion of said knives into said oven, air inlet means for balancing the gas pressure in said combustion chamber, means cooperating with said air inlet means to control the passage ofair therethrough and to provide supports interiorly of the oven for said knives, and means for regulating the velocity of the combustion gases through said flue.

'6. An oven for heat treating materials comprising a body provided interiorly with superposed chambers in open communication with each other throughout the bottom of the upper chamber, a longitudinally open flue connected with the upper chamber and having its exit end open to the atmosphere, supporting means contiguous to the communication between said chambers for supporting the material within said oven, a movable closure for closing the longitudinal opening of .said flue to form a wall thereof and adjustable to provide access to said opening for insertion of said material into said opening, an oil burner connected with the lower chamber, and means for regulating the velocity of the combustion gases through said flue.

7. An oven for heat treating materials com prising a body provided interiorly with superposed chambers in open communication with each other throughout the bottom of the upper chamber, a longitudinally open flue connected with the upper chamber and having its exit end open to the atmosphere, supporting means for supporting the material within said oven, a movable closure for closing the longitudinal opening of said flue-to form a wall thereof and adjustable to provide access to said opening for insertion of said material into the oven, and an oil burner connected with the lower chamber.

8. An oven for heat treating materials comprising a body provided with interior chambers located one above the other in open communication with each other throughout their respective lengths, a longitudinally open flue connected with said chambers and having its upper exit end open to the atmosphere, means for developing combustion gases insaid chambers, and movable means forming a wall of said flue by closing the longitudinal opening thereof and adjustable to provide access to said opening for insertion of the material into the oven.

9. An oven for heat treating materials comprising a body including a front wall and provided with communicating interior chambers, a flue longitudinally open in said front wall of the body connected with said chambers and having its exit end open to the atmosphere, an oil burner connected with one of said chambers, means for admitting air thereto, and movable means located exteriorly of said flueand forming a wall thereof by closing the longitudinal opening thereof, said movable means being adjustable to provide access to said opening for insertion of the material into the oven.

HAROLD CASE. 

